It is known that, when nerves present in the vicinity of the adventitia of the renal artery are cauterized, the blood pressure decreases over a long period of time. Thus, an application of the knowledge to the treatment of hypertension has been expected. Such a technique of cauterizing the nerves in the renal artery is referred to as renal artery sympathetic nerve ablation or renal denervation. As one renal artery sympathetic nerve ablation, a technique is mentioned which includes inserting a balloon catheter having an electrode into the right and left renal arteries, heating is performed from the intracavity of the renal arteries by generating heat by the electrode, and then transmitting the heat to the adventitia of the renal arteries for cauterizing the nerves.
However, when heat of about 60 to 70° C. required for cauterizing the nerves is transmitted from the intracavity to the adventitia of the renal arteries, there are concerns about problems that adverse effects, such as an edema and a thrombus, arise with high frequency due to the heat given to the intima. Moreover, since it takes several minutes to transmit the necessary heat from the intracavity to the adventitia, heat and pain may be given to a patient during the transmission.
To address the problems described above, a device has been proposed which includes guiding a pulse laser to the renal artery using a catheter, condensing the pulse laser to the adventitia of the renal artery by a condenser lens, and then causing multiphoton absorption at a focal position to perform ablation to the adventitia at the focal position (Patent Literatures 1 and 2).